Etiology of sugarcane wilting syndrome: determination of favorable conditions for infection and the effect of abiotic stresses concurrent with Phaeocytostroma sacchari infection.

• Grant number: 24/22738-6
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: April 01, 2025
• End date: March 31, 2026
• Field of knowledge: Agronomical Sciences - Agronomy - Plant Health
• Principal Investigator: Lilian Amorim
• Grantee: Pedro Catão Guimarães
• Host Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil

Abstract

The sugarcane wilting syndrome (SWS) is a recent anomaly in Brazil. The incidence of SWS is increasing in Brazilian sugarcane-producing regions. Yield reductions of up to 25% have been attributed to this syndrome, which has been observed in various sugarcane varieties across at least six states in the country. The symptomatology of this syndrome is characterized by wilting in the median portion of mature stalks, with no symptoms observed at the plant's base or apex. Internally, the tissues exhibit discoloration, spongy texture, and a characteristic acrid odor. The presence of rot within the symptomatic area is common, and various pathogens have been isolated. However, Phaeocytostroma sacchari is the most frequent pathogen associated with disease symptoms. This pathogen is endemic to Brazil and causes sugarcane rind rot, a secondary post-harvest disease. Very little information is available in the literature about P. sacchari and SWS. Therefore, this project aims to determine the temperature conditions and wetness durations favorable to the pathogen and stalk infection, as well as to evaluate the effect of abiotic stresses concurrent with P. sacchari infection on the development of SWS symptoms. To achieve this, in vitro, ex vivo, and in vivo assays will be conducted. Pathogenic growth response curves and conidial germination response surfaces will be determined as a function of temperature and different wetness durations. The development of symptoms in detached stalks will also be evaluated using different inoculation methods. The effect of high temperatures and water limitation on disease progress will be assessed in assays with potted mature plants under controlled conditions.